Introduction

With the rapid advancement of science and technology, LiDAR (Light Detection and Ranging), as a cutting-edge active optical remote sensing technology, plays a vital role across various industries. From intelligent transportation and autonomous driving to industrial automation, LiDAR has become an integral part of modern life. In a LiDAR system, the performance of the light source directly determines key parameters such as detection range, accuracy, and reliability. The 905nm multi-junction pulsed laser diode has emerged as one of the core light sources in LiDAR due to its unique performance characteristics and advantages. This paper systematically introduces the basic principles, application advantages, and practical use cases of 905nm multi-junction pulsed laser diodes in LiDAR.

Basic Principle of 905nm Multi-Junction Pulsed Laser Diodes

• Working Principle: Multiple PN junctions are vertically integrated within a semiconductor substrate. Each junction can independently generate laser emission and operate simultaneously when driven by current pulses.

• 905nm Wavelength: This refers to the output wavelength of the laser. The 905nm band is currently the most widely used emission wavelength in commercial LiDAR systems. It offers a good balance of eye safety and strong atmospheric penetration, meeting the requirements of most outdoor and automotive scenarios.

• Multi-Junction Structure: Multiple active layers are connected in series using tunnel junctions. This structure enhances current throughput and peak output power without increasing chip area, improving overall efficiency and thermal stability—key benefits in modern semiconductor optoelectronic device design.

• Pulsed Characteristics: Compared to continuous-wave lasers, pulsed lasers can release extremely high energy in short durations, resulting in high peak power. Pulse width and repetition frequency can be precisely controlled to enhance ranging resolution and signal clarity. Additionally, the low duty cycle (~0.1%) of the 905nm multi-junction pulsed laser diode minimizes thermal effects, making it ideal for compact laser system designs.

Application Advantages of 905nm Multi-Junction Pulsed Laser Diodes

• Low Detection and Structural Cost:
  905nm lasers operate within the sensitive range of silicon-based photodetectors, which are widely available, cost-effective, and highly integrated. This makes the 905nm multi-junction pulsed laser diode advantageous in terms of overall system cost. Furthermore, the multi-junction structure enhances output power without increasing chip size or cost. As semiconductor manufacturing technology continues to advance, the cost of producing multi-junction chips is decreasing, further driving down the total system cost.

• Miniaturized Design and Easy Integration:
  The compact form factor of 905nm multi-junction laser diodes—some as small as sub-millimeter—makes them ideal for integration into miniaturized LiDAR systems. Additionally, these diodes can be fabricated as arrays (e.g., 1×N or 2D) to achieve higher power output and enable flexible beam control.

• Extended Detection Range:
  Detection distance is a critical performance metric in LiDAR applications. The high peak power of the 905nm multi-junction pulsed laser diode significantly extends the system's detection range. In vehicle LiDAR, this allows for early obstacle detection at long distances, providing essential reaction time for autonomous driving systems.

• High Measurement Accuracy:
  The accuracy of distance measurement depends on the precision of the laser pulse timing. The 905nm multi-junction pulsed laser diode supports ultrashort pulse generation with precise control of pulse width and repetition frequency. This enables the LiDAR system to accurately measure time-of-flight and minimize ranging errors.

Practical Applications of 905nm Multi-Junction Pulsed Laser Diodes in LiDAR

• Vehicle LiDAR (ADAS and Autonomous Driving):
  In intelligent vehicles, the 905nm multi-junction pulsed laser diode provides high sensitivity and long-range detection for LiDAR, delivering reliable data for ADAS (Advanced Driver-Assistance Systems) and autonomous driving systems.

• Industrial Automation and Robotic Navigation:
  Thanks to their high power output and repetition frequency, these diodes are widely used in industrial automation for robot positioning, navigation, and obstacle avoidance.

• Intelligent Transportation and UAV LiDAR:
  The fast response time and strong environmental adaptability of the 905nm multi-junction pulsed laser diode make it well-suited for traffic monitoring LiDAR systems, such as speed detection and violation enforcement, as well as UAV-based mapping and navigation.

Conclusion

The 905nm multi-junction pulsed laser diode has quickly become the core light source for next-generation LiDAR systems due to its high power output, high-frequency emission, compact design, and excellent reliability. It is widely used in vehicle LiDAR, industrial automation, intelligent transportation, and UAV applications. With continued technological progress, these laser diodes are expected to play an even more prominent role in future high-end and emerging fields.

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